PLE-2419

A 43-year-old hypertensive man comes to the physician because of headache, blurred vision, and confusion for 2 days. He has not had weakness or numbness, difficulty ambulating, chest pain or discomfort, diplopia, or vertigo. Blood pressure is 190/120 mmHg on presentation. The neck is supple. Fundoscopic examination shows enlargement of optic discs with indistinct border. Blood vessels near the discs are indistinct. The lungs are clear to auscultation. There is an S4 with no murmur. Neurologic examination shows no abnormalities. What is the most likely diagnosis?